Satellite weather via FM

You could do that in flight. However, there are a few difficulties:

1. Antenna location is critical; otherwise turns may disrupt reception
2. Since 137MHz is very close to the airband, reception disruption is almost unavoidable when transmitting
3. Images are monochrome 2080×909 pixels, with 2 scan lines per second, so roughly 8 minutes per picture
4. whether you can receive an image depends on whether a suitable satellite is in view

It seems that APT is on its way out, the last satellite carrying the payload has been launched in 2009. It was supposed to be replaced by LRPT, but plans have apparently mostly been cancelled. Satellites also carry HRPT, but receiving that would be very inconvenient, because it needs a high gain antenna (satellite dish with tracking).

All in all it’s a lot less hassle to use a satellite datalink to download the image you want